(1) Field of the Invention:
The present invention relates to a toner cleaning apparatus in electrophotography. More particularly, the invention relates to an apparatus for effectively peeling and removing a residual toner from the surface of a photosensitive material by using an elastic doctor blade while preventing abrasion of the surface of the Photosensitive material.
(2) Description of the Prior Art:
Referring to FIG. 1, in the electrophotographic process, the surface of a photoconductive photosensitive material 1 is charged by a charger 11 and is exposed imagewise to light through an optical system 12 to form an electrostatic latent image. This electrostatic latent image is developed with a toner 14 by a developing mechanism 13, and the formed toner image is electrostatically separated and transferred to a transfer sheet 15 by a charger 16. After the transfer, the toner left on the surface of the photosensitive material is removed by a cleaning mechanism 2, if necessary after removal of electricity by a charger 17. The reproduction is carried out by repeating the foregoing operations. The toner left on the surface of the photosensitive material after the transfer step is electrostatically attracted to the surface of the photosensitive material, and removal of this residual toner by cleaning is not always easy.
Cleaning of toners has heretofore been performed by a method using a fur brush, a method using an elastic blade or a method using a magnetic brush. The fur brush method involves a problem of scattering of the toner and the magnetic brush method is defective in that an expensive magnet-containing cleaning sleeve should be independently disposed. Furthermore, in the case where the developing sleeve is used also for the cleaning operation, the reproduction cycle is prolonged because of the cleaning operation. The method for effecting cleaning by sliding contact of the surface of the photosensitive material with the elastic blade is advantageous in that the mechanism and operation are simple. However, in order to remove toner particles from the surface of the photosensitive material against the electrostatic attracting force to the surface of the photosensitive material, a considerably great pressing or contacting force should be imposed on the top end of the blade, resulting in scratching of the surface of the photosensitive material or shortening of the life of the photosensitive material.